1. Field of the Invention
This invention relates to a new heat exchanger control for such a system as well as to new methods of making such a heat exchanger control system and such an electrically operated control valve means.
2. Prior Art Statement
It is known to provide a heat exchanger control system comprising a source of fuel, a burner means for being interconnected to the source of fuel for issuing the fuel therein for burning at the burner means, means for supplying combustion air to the burner means to aid in the burning of the fuel that issues therefrom, electrically operated control valve means operatively interconnected to the burner means and the source of fuel for interconnecting the source of fuel to the burner means when the electrically operated control valve means is in a first operating condition thereof and for disconnecting the source of fuel from the burner means when the electrically operated control valve means is in a second operating condition thereof, and a differential pressure operated electrical switch means operatively interconnected to the electrically operated control valve means to tend to cause the electrically operated control valve means to be in the first condition thereof when the differential pressure operated electrical switch means is in a first condition thereof and to tend to cause the electrically operated control valve means to be in the second condition thereof when the differential pressure operated electrical switch means is in a second condition thereof, the differential pressure operated electrical switch means being operatively interconnected to the means for supplying combustion air and being adapted to be operated thereby from the second condition thereof to the first condition thereof only when the pressure value of the air being supplied to the burner means is at or above a predetermined value whereby sufficient combustion air will be supplied to the burner means before the electrically operated control valve means causes fuel to issue from the burner means, the electrically operated control valve means and the differential pressure operated switch means being separate units so as to be selectively and separately disposed in the system. For example, see FIG. 12 of this application for a schematic showing of such prior known system.